1. Field of the Invention
The present invention relates to a turbine engine, and particularly to a jet flap arrangement for producing a pre-swirl at the compressor inlet.
2. Description of the Prior Art
Attempts have been made in the past to overcome the problem of engine surge at off design modes in gas turbine engines while producing pre-swirl in the compressor inlet by bleeding air interstage of the compressor and advantageously using this bleed air to form a jet flap on a hollow strut in the compressor inlet such as described in U.S. Pat. No. 4,222,703, Schaum et al, 1980.
The Schaum et al patent describes a hollow strut in the compressor inlet preceding the first compressor stage communicating with a passage and a bleed valve for bleeding air from interstage of the compressor. The hollow strut has a slot near the trailing edge of the strut for producing the jet flap. The strut extends between the shroud and the hub in that portion of the engine thereof. It has been found that the inertia of the bleed air moving in the strut from the shroud to the hub will cause the air distribution at the slot forming the jet flap to be unequal and for the highest pressure to be nearest the hub, thereby affecting the pre-swirl at the compressor inlet.